Clinical Application Of ～(18)FDG PET In Thoracic Tumor Patients With Radiotherapy And The Influence Of Radiation Pneumonitis

Background and Objectives: Positron Emission Tomography (PET) imaging with fluorodeoxyglucose (FDG) plays an important role in the management of patients in the course of radiotherapy. Radiation pneumonitis is a common complication in radiation therapy of thoracic tumor patients. Radiation pneumonitis with increased FDG uptake is often difficult to be differentiated from tumor recurrence or metastasis. However, the literature on this subject is scarce. This study was performed to evaluate the clinical uses of FDG PET in radiation therapy of thoracic tumor patients and the influence of radiation pneumonitis on FDG PET diagnosis.Methods: Fifteen thoracic tumor patients treated with radiotherapy were included (10 men and 5 women; mean age 53 ± 16.8 years, range, 25-86 years; 6 with lung cancer, 4 with breast cancer, 3 with esophageal cancer and 2 with Hodgkin's lymphoma) during the period from March 2001 to April 2003. Serial PET imagings were performed before, during, and after the end of radiotherapy (a total of 59 PET scans). Visual and semiquantitative analyses were used to analyze the FDG PET images.Results:Ⅰ . The value of FDG PET in the course of radiotherapy (RT)13 patients underwent PET imagings before RT. Among 6 patients post operations and/or chemotherapy with residual tumor, metastases were detected in 2 patients with negative CT, leading to a change of treatment planning and increase of radiation volume.1 patient underwent FDG PET imaging during radiotherapy, and in comparison with the pretherapeutic study the foci became smaller and uptake lower, indicating good response.In 6 of 15 patients, posttherapeutic PET imaging detected recurrence or metastases. Among them, case No. 3 and No. 4 were asympomatic.Ⅱ. Radiation pneumonitis1. The clinical symptoms of radiation pneumonitis...